<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .content {
      width: 1190px;
      margin: 0 auto;
      background-color: orange;
      height: 800px;
    }

    .box {
      margin-right: -10px;
    }

    .item {
      width: 230px;
      height: 322px;
      background-color: purple;
      float: left;
      margin-right: 10px;
    }

    /* 有可能有兼容性问题 */
    /* .item:nth-child(5n) {
      margin-right: 0;
    } */
    /* 麻烦 */
    /* .item.last-item{
      margin-right: 0;
    } */
  </style>
</head>

<body>
  <div class="content">
    <div class="box">
      <div class="item item1">1</div>
      <div class="item item2">2</div>
      <div class="item item3">3</div>
      <div class="item item4">4</div>
      <div class="item item5 last-item">5</div>
    </div>
  </div>
</body>

</html>